- Synthesis of 1,3-dialkylimidazolium-2-carboxylates by direct carboxylation of 1,3-dialkylimidazolium chlorides with CO2
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1,3-Dialkylimidazolium-2-carboxylates 1a and 1b are obtained in good to excellent yield and selectivity by carboxylation of the corresponding 1,3-dialkylimidazolium chloride salts with a CO2/Na2CO3 system at temperatures ranging from 80 to 135 °C. The effect of temperature and reaction time on the yield and the selectivity of the carboxylation products has been studied. Coupling the CO2-based synthesis of 1,3-dialkylimidazolium-2-carboxylates with the transcarboxylation reaction described earlier [Tommasi, I.; Sorrentino, F.; Tetrahedron Lett., 2005, 46, 2141] allows us to set up a new synthetic procedure for the synthesis of organic carboxylates and alkylcarbonate anions avoiding the use of strong bases.
- Tommasi, Immacolata,Sorrentino, Fabiana
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- Imidazolium carboxylates as versatile and selective N-heterocyclic carbene transfer agents: Synthesis, mechanism, and applications
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N,N′-Disubstituted imidazolium carboxylates, readily synthetically available, isolable, air- and water-stable reagents, efficiently transfer N-heterocyclic carbene (NHC) groups to Rh, Ir, Ru, Pt, and Pd, to give novel NHC complexes, e.g., [Pd(NHC)3/
- Voutchkova, Adelina M.,Feliz, Marta,Clot, Eric,Eisenstein, Odile,Crabtree, Robert H.
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- Novel synthon for incorporating 1,3-dimethyl-imidazolium group into molecular architecture
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The synthesized 1,3-dimethylated imidazolium-carbaldehydes serves as synthons for incorporating a permanently cationic imidazolium group into molecular framework. The utility of new synthon was demonstrated in a variety of reactions: Knoevenagel, Wittig,
- Berezin, Mikhail,Achilefu, Samuel
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- Imidazol-2-and-4-ylidene by decarboxylation. Studies on the cross-conjugated mesomeric betaine-alkaloid norzooanemonine and its pseudo-cross-conjugated isomer
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1,3-Dimethylimidazolium-2-carboxylate and -4-carboxylate (norzooanemonine), which belong to two distinct classes of heterocyclic mesomeric betaines, undergo thermal decarboxylations to the N-heterocyclic carbenes imidazol-2-ylidene and imidazol-4-ylidene, respectively. These carbenes can be detected by ESI mass spectrometry and can be trapped by isocyanates to imidazolium-amidates, the structure of which was proved by independent syntheses. We performed calculations to characterize the different types of conjugation in the imidazolium-carboxylates. This journal is The Royal Society of Chemistry.
- Schmidt, Andreas,Beutler, Ariane,Albrecht, Marcel,Snovydovych, Bohdan,Ramirez, Francisco Javier
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p. 287 - 295
(2008/09/21)
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- Process for the preparation of 1,3-dimethylimidazolium 4-carboxylate
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1,3-Dimethylimidazolium 4-carboxylate is prepared by reacting 1-methylimidazole with dimethyl carbonate optionally in the presence of a solvent in accordance with the following reaction scheme:
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- Preparation of cyanoacetic esters
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Cyanoacetic esters are prepared by reacting a corresponding monochloroacetic ester with hydrogen cyanide in the presence of a base, where the base is a compound selected from the group consisting of tertiary amines, salts of carbonic acid, salts of carbonic acid monoesters, salts of carboxylic acids, amidines, guanidines and aromatic N-heterocyclic compounds.
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